Odor observer and odor meter



Nov. 15, 1.938.

G. M. FAIR ET A1.

onon oBsERvER AND onon METER Filed March 19. 1955 Sheets-Sheet 1 Nov.15, 1938. G. M. FAIR /E-r AL ODOR QBSERVER AND ODOR METER 7 sheets-sheet2 Filed March 19, 1935 OOOUUUUU- NOV. 15, 1938. G, M FAlR ET AL2,136,844

ODOR OBSERVER AND ODOR METER Filed March 19. 1935 7. Sheets-Sheet 3 Nov.l5, 1938i G. M. FAIR ET A1.

ODOR OBSERYER AND ODOR METER 7 Sheets-Sheet4 4 Filed March 19. 1935 Nov;l5, 1938. G. M. FAIR ET AL 2,136,844

` ODOR OBSERVER AND ODOR METER Filed Maron 19, 1955 'r sheets-'sheet 5 f124 fmr 145/' www 106)' l .Lf-10 m9451933.. GMFAIRTAL v Y2,136,844

yODOR OBSERVER AND ODOR METER Filed March 19, 1935 Y '7 Sheets-Sheet 6 fJ Z9 'tig' n 4f a i5 s 54 fs 152 f I?? vez/JOWS @www 772.1%?

Nov. l5, 1938. G. M. FAIR ET Al. 2,136,844

` ODOR OBSERVER AND ODOR METER Filed March 19. 1935 7 Sheets-Sheet '7Patented Nov. y15,1'938 v ODOR OBSEBVEB AND ODOR METER oorden M. Een andwilliam Firth weils, cambridge, Mass.; said Wells assigner to said FairApplication March 19, 1935, serial No. 11,894

33 Claims.

The presentlinvention relates to apparatus for measuring or determiningodors.

Unlike the senses of vision and hearing, for

` example-affected, as they are, by light and sound Waves that aremeasurable orvdetaehablev by inanimate instruments-the sense of smellcan not be measured or determined except by some living object. Allproposals for determining or measuring smell must, therefore, dependdirectly upon physiological functions. It so happens that the organs ofsmell are exceedingly sensitive; they will respond to what areessentially chemical or physico-chemical changes so extremely minute asn ot to be detectable by chemical or physical analysis. Like all sensergans, however, they are subject to the Weber-Fechner psychophysicallaw,l

so that a change in odor concentration is not perceptible unless thechange is great enough to constitute a definite functionalincrement-positive or negative, as the case may be-of the `actingconcentration or stimulus. It has long been recognized that it isphysiologically impossible to measure smaller changes, because thesmelling organs will not respond to such smaller changes.

It is, therefore, futile to attempt any greater accuracy of measurement,and records appearing to show greater precision-must necessarily beillusory or fictitious. Another factor that, though equally wellunderstood, has "not, apparently, been so fully and adequatelyconsidered in the design Vof smell-detecting and/or smell-measuringdevices, is the factor of physiological fatigue. Unlike other senseorgans, the organs of smell become very rapidly dulled, with theresultthat protracted smelling of an odor exhausts the power torecognize it. This isV particularly true` if the strength of Hrthe odoris great. If the odor is near the threshold, the fatigue will be small.Unless the organs of smell are utilized at the right'mo- 40 ment,therefore, and for a moment only, and the odor is very dilute, theresulting measurement becomes impaired.

An object of the present invention, accordingly,

is to provide new and improved apparatus for measuring or determiningodors, using dilution processes, and activation by the nose.

Another object is `to provide novel apparatus dependent. for itssuccessful operation, upon intelligent use of the said Weber-Fechnerlaw.

Another object is to provide an easily determinable scale of odormeasurements.

Another object isl to provide an instrument for determining Athedilution required to bring a given' odor toan approximate thresholdvalue, asaI (Cl. 'J3-51) means of measurement of the intensity of theodor.

Still another object is to provide novel apparatus adapted for promptand momentary use, so as to prevent errors that might otherwise arise 5as a result of fatigue.

Another object is to test the odor by diluting it to the thresholdvalue, or near it, before the odor is sensed, so as to reduce errorsthat might otherwise arise as a result of fatigue.

Another object ls to provide means for compounding odors by testing theodor intensities of the substances that should be mixed to give thedesired compound odor.

Another. object is to provide means for neutralizing odorsphysiologically by testing the odor intensities of the substances thatare to be mixed to neutralize each other physiologically.

Another object is to make vit possible tovuse the nose to draw the rawordiluted odor into the nose 20- without auxiliary flow-inducing apparatusand to have the nose induce` the movement of both odor and diluting airtowards the olfactory areas in the nose.

Still a further object is to design novel smelldetecting4 orsmell-measuring apparatus particularly adapted to the anatomy of thenose and its relation to the olfactory cleft, near the highest point ofthe nasal cavity, so as to make it possible for the odors under test toreach the olfactory regions promptlyand with-certainty, instead ofley-passing into the mouth through the passages connecting themouth withthe nose.

Other and further objects will be explained hereinafter, and will beparticularly pointed out 35 in the appended claims.

The invention will now be explained in connection with the accompanyingdrawings. in .which Fig. l is a longitudinal section illustrating oneembodiment of the invention comprising both 40 an odor meter and an odorobserver; Fig. 2 is a'u corresponding perspective, the telescopicallyadjustable tubes being shown detached; Figs. 3, 4,

' 5 and 6 are fragmentary perspectives showing the telescopicallyadjustable tubes in different posi- 45 tions of adjustment; Fig. '1 is afragmentary perspective of a modification; Figs. 8, 9 and 10 arelongitudinal sections, 'corresponding to Fig. 1, of furthermodifications; Fig. 11 is an elevation, partly in longitudinal section,of a further modi- 50 flcation; Fig. 12 is a fragmentary elevation,partly broken away, looking in the direction of the arrow I2, Fig. 1l;Fig. 13 is an elevation corresponding to Fig. 12 of a modification, apart being broken away, for clearness; Fig. 14 is anelevation of a Mscale than in Fig. 19, showing the parts in dif-" ferent positions ofadjustment; Fig. 28 is a side elevation of still a further modificationembodying an odor observer: Fig. 29 is a fragmentary end elevation of'the same, partly in longitudinal section; Fig. 30 is an elevation of amodifled detail; Fig. 3l is an elevation, partly in longitudinalsection, of still a further modification; Fig. 32 is a front view of thesame partly in section; and Fig. 33 is a section taken upon the line33-33 oi' Fig. 32, looking in the direction of the arrows, but upon alarger scale.

The threshold value of an odor is defined as the smallest amount of theodorous substance required to stimulate the olfactory nerves and obtaina conception of, or sense, the odor. The measurements of arithmeticallyequal, successive units of sensation, that are just perceptible, will,according to the before-mentioned, psychophysical law of Weber andFechner, require stimuli that vary in geometric ratio. A plot, usig ageometric or logarithmic scale for odor concentration, and an arithmeticscale for intensity of sensation, therefore, wlll yield a straight line.

'I'he next-higher, odor concentration, above the thresholdconcentration, thatis just distinguishable, for example, is somemultiple of the threshold concentration. 'I'his value may vary fordifferent odors and different observers; but a readily recognizeddifference is obtained by doubling the odor concentration.`

'I'he next-higher concentration that is readily distinguishable, in thesame way, is four times as great; the next-higher, eight times as great;and the successive, next-higher, concentrations, sixteen times,thirty-two times, etc., as great as the threshold concentration. 'I'hereis thus developed a rational scale oi' odor, threshold intensities basedupon the binary, geometric progression 1, 2, 4, 8, 18, 32, etc., theodor intensity being expressed in terms of the, threshold value of theodor. The odor vscale is, therefore, established as a power orexponential, scale,

2, 21, 21, 23, 24, 2, etc.

By analogy with the practice of recording hydrogen-ion concentration,this exponential scale may be designated by the symbol p0; it beingremembered, however, that p0 is the logarithm to the base 2 (and not, asin the case of pH, to the base 10) ofthe odor, threshold intensity orconcentration. The symbol p0 4, for example, may represent an odorthreshold intensity of 24:16. When expressed in grams of odoroussubstance per milliliter of air, this threshold value is called an"olfacty". The symbol p04, for example, may, therefore, represent alsoan odor intensity of 24:16 olfacties. Indirectly,v therefore, the odorconcentration may also be 'expressed in grams per milliliter, if thethreshold intensity of the odor is known.

The modifie ion illustrated in Figs. 14 to 18 will be descri first,because it precedes the other modifications historically. A fullerdescription may be found in an article in the Journal of the New England*Waterworks Association, Vol. LVII, September, 1983, commencing at page248, entitled, On the determination of odors and tastes in water.

Letting it be assumed that itis desired to measure the threshold valueof an odor in a gas, it is proposed to dilute this odor with fresh,odor-free air, in geometric ratio, to vits approximate threshold point.

A frame 2 may rest on an intermediately disposed bottom 4, in its normalposition, or on either of two bottoms 6 and l, 'that are inclinedlydisposed at a 45-degree angle to the left and to the right,respectively, of the bottom 4. In the frame 2, there is suspended aburette comprising two hollow spheres I 9 and I2, the lower portions ofwhich are connected together by a pipe I4. A pipe i6 inclines upward andto the right, from -the sphere I Il, to afour-way stopcock i8. A pipe29, leading from the sphere -I2, similarly inclines upward, but,to theleft, to the stopcock I8. The stopcock I8 is connected with two furtherpipes 22 and 24. 'I'he pipe 22 is adapted to be connected, by tubing 23,with a receptacle 28 for an odor-containing gas. 'I'he pipe 24 isadapted to be connected with the lower end of an odor observer,comprising preferably a Aglass or metal tube I9, the upper end of whichis provided with a stopper I2 in which is mounted a forked, glass ormetal tube 34 having integral therewith two nose pieces I6 and I9,disposed side by side. The nose pieces 38 and 3l are adapted to beinserted into ones nostrils, to direct the odor in the tube Ill directlytoward the olfactory `cleft, in response to a light sni'. 'I'hey fitinto the nose in such a way that penetration of outside air isprevented.

If desired, the stopper l2 may contain two separate glass tubes Il and4I, as illustrated in Figs. 7 and 19 to 21, each rotatably adjustable inthe stopper, and each having an angularly disposed nose or nostrilpiece, shown at 43 and 45. Adjustment of these nose pieces 43 and 45 maythus be made for different nostril distances. The same result may beeffected by means of metal nose pieces |58 and |59, as illustrated' inFigs. 3l and 32, adjustable, for different nostril distances, by meansof screw threads |60 in the upper wall |62 of a metal mixing chamber|64. A single nose piece 38 and Il may, however,be employed.

It has heretofore been proposed to insert the observers nose into aregion containing the odors to be tested. Altogether aside from the factthat the olfactory organs become fatigued, during the long exposure ofthe nose in such region, there is a tendency for the currents ofodor-containing Vgas under test, to which the nose is exposed, to travelinto the nasal chamber and into the pharynx, without rising high enoughto sweep past the olfactory surfaces, unless one sniffs. This is truewhether the respiration is deep or shallow. A deep breath, in fact, maydefeat its own object by preventing the relatively slow diifusion andgradual changes that are effective, during quiet breathing, to producethe desired sensation of smell, even with weak stimuli. If the face ofthe observer is exposed to odorous gas, one may also cover the face withthe odorous gas and change response of the nose to the odor actuallytested.

According to the present invention, this dimculty is overcome, and theldetection of the odor made more precise and delicate, through the mediumoi' the nose pieces Il and Il, or 43 and 4l, or I and I Il, which reduceto a minimum the volume of the odor-containing gas in contact with thenose, and ensure that the odor-containing currents shall reach directlythsolfactory 7l areas, by being directed toward the olfactory cleft.results, with only a single, light snii, and without errors introducedby fatigue.

The parts of the apparatus including the elements 24, 30, 32, 34, 36 and38 may be termed an odor observer, because they serve merely to observethe odor. nected with an odor meter for measuring the odor intensity, aswillpresently be described. The combination of the odor observer and theodor meter may also be referred to as an odor meter. Most of themodications illustrated and described herein, as, for example, Fig. 1,are odor meters. The modification illustrated in Fig. 28, however, is anodor observer, and not an odor meter. l

In the normal position of the apparatus, in which the frame rests on itsintermediately disposed bottom .4, as illustrated in Fig. 14, mercury orany other suitable fluid Il), contained in the spheres I and I2,occupies the position shown., half illling the spheres I0 and I2.Mercury is a satisfactory uid for many odors which are not taken intosolution to a measurable extent, or do not enter into combination withthem; Its high density, furthermore, facilitates transfer of the odorfrom the receptacle 2B to the spheres I0 and I2, as will presently beexplained. The modifications of the invention illustrated in Figs. lV to13 and 19 to 33, which render it unnecessary to employ mercury oranother fluid, eliminate sources of error that `.may be introduced incases where the'odor-containing gas is .i attacked by the mercury orother iluid Ml.

In line with what has been said above about the odor scale, theprocedure that will ordinarily be found most useful calls for ilrstfilling the burette of the twin-sphere odor meter with the original odorfrom the receptacle 2B at a time when the instrument is changed from theposition illus tratecjiin Fig. to the position illustrated in Fig.

fI'he frame 2 is first tilted, so as to rest on its inclined bottom 6,as shown in Fig. l5. The mercury' 40 is thus caused to ow out of thesphere I2, so as to ll the sphere lll. The cock I8 is now turned, so asto connect the receptacle 28 with the sphere IIJ, after which the frameis tilted slowly to the position indicated in Fig. 16,' so as to rest onlthe bottom 8. The mercury, thus iiowing out ofthe sphere I0 and intothe sphere I2, forces the odor to enter from the receptacle 2t,into thesphere I il. This is permitted by an air vent 4l at the upper end of thereceptacle 2t. The stopcock I8 is now returned to its original position,followed by the return of the frame 2 to its normal position, in whichit restspn its base Il, as illustrated in Fig. 17. The odor thus becomesequally distributed in the two spheres Ill and I2. The next operation isto turn the stopcook l again, so as to connect the sphere It with theodor-observer tube 3U. By now slowly tilting the frame 2 to the positionillustrated in Fig. 18, so as to rest on its bottom 8, the mercury willbe caused to ow into the sphere I2. The odor in the sphere I2, which ishalf the total volume, is thus lexpelled into the odor-observer tube tt.4The volume of displaceable odor may be about 220 c. c. If theodor-observer tube 30 holds about 60 c. c., all the air in the tube 3Uwill be driven or flushed out of the tube 30 andthe tu will then becomefilled with the pure odor. The odor may be observed ordetected bysniillng directly through the nose pieces 36 and il (or It is thuspossible to obtain 'the' best.V

This odor observer is con' 43 and l5), as the odor is beingdisplacedfrom the burette, or the odor-observer tube 30' may be detachedand the odor sniffed.

At, the same time that the odor isexpelled from the sphere I2into thetube 30, an equal.

amount of air is, of course, drawn into the sphere I0, so ascorrespondingly to add to the odor in the sphere III an equal amount ofair. The odor in the sphere III thus becomes diluted in the ratio of oneto two. The process .is now repeated, to displacehalf the resulting,diluted volume into the odor-observer tube 30, followed by observationof the odor.

To this end, the next step is to return the stopcock I8 to its normalposition and to return the trarne 2 to the position, illustrated in Fig.

- 17, in which it rests on its bottom l. The diluted odor thus becomesdivided equally between the spheres I0 and I2. Thedisplacement-anddilution procedure is then repeated. This is continueduntil the threshold dilution is passed, and the odo-r is no longerperceivable, thus producing odor-free air; or the processymay be stoppedat any desired point, corresponding to the bland or mixture sought bythe observer, as where it is desired to obtain a particular blend ofperfume. Instead of diluting with odor-free air, it is possible toattach a pipe 22 to other odor containers similar to the receptacle 28by tubing similar rto 26, and draw in a gas or odor other than air fordilution or blending purposes.

The number of dilutions is-the p0 value. 'I'he threshold number isobtained by raising 2 to a power equal to the number of dilutionsrequired to reach the. threshold value for the given strength of theodor.

The stopper 32 is shown in Fig. l at the upper end of a metal or glwsmixing tube 42, having openings in lts sides at varying levels.Chromium-plated brass is a suitable metal, as it does not aiect most ofthe odors to be tested. But other metals or metallic platings may beemployed. Glass, or other inert substances, too,

sok

may be used. .The uppermost opening is shown r cessively, andln order,the openings 64, 62, 60, 58,

Elli, 5t, 52, bil, #I8 and It, and '44, as the tube 66 is adjustablymoved upward into the tube 42. The top end of the tube is closed, asshown at 68, except that it is provided with an opening 1li. I

The openings 44, Mi, M, 50, 52, 54, 56, 58, 6U,

V`t@ and 'I0 are preferably all of the same shape and area, so as toprovide hydraulically equal ows.

The space d@ in the tube 42, between the stopper 32 and the top 68 ofthe tube 66, constitutes an adjustable mixing chamber into which gasesmay be drawn through the said openings by sniing' through thenosepieces..

When the tube 66 occupies the position illus--r trated in Fig. 3, theodor-containing gas from a vessel 12 (Fig. 1) alone can be drawn intothis `adjustable chamber, through the opening 10.

The odor thus drawn into the nostrils corresponds to a zero reading ofthe scale.

An odor can not be detected unless in gaseous from, as m the air- 1t cannot be breathed while dissolved in a liquid.

If the vessel 'i2 contains water or other liquid, such as a liquidperfume, it may become charged with the odor-containing gas by, say,shaking up the liquid, or by using an atomizer I4 that discharges intothe vessel 12, air being allowed to enter or leave the vessel 12 throughan opening 16. If it is desired to measure the odor of a solid -11 (Fig.8) in a tower provided in the receptacle 18, a closed, central screenedchamber llmay be provided into which the bottom of the tube Si may beinserted. The odor from the solid 11 will travel into the' chamber Iland will be drawn up the tube I8, through the opening 10, into the saidadjustable mixing chamber 4l in the tube 42, yet

, the screen will hold the solid away from the central chamber l0 of thereceptacle 1I, into which the tube II may be inserted.

When the tube Il occupies the next lower po-l sition of adjustment(Figs. 1, 8 and 9), the adjustable, mixing chamber 4I in the tube 42will contain the said odor-containing gas, drawn into the adjustablechamber through the opening 10, and also an equal amount of air blendedtherewith, the air being drawn into the adjustable chamber through theopening 44. 'I'he adjustable, mixing chamber 4l will, therefore, containa one-to-two, diluted mixture of the odor-containing gas. In thenext-lower position of the tube B8, illustrated in Fig. 4, air willenter the chamber 49 through the three openings 44, 48 and 48, and thechamber will thus contain a one-to-four mixture ,of the odor-containinggas.

In the next-lower position of the tube 88, illustrated in Fig. 5, airwill enter the chamber through the seven openings 44, 46, 4B and Bil.The dilution of the odor-containing gas in the chamber will now,therefore, be one to eight.

In the next-lower position of the tube 88, illustrated in Fig. 6, airwill enter through the eight additional openings i2, so that thedilution of the air-containing gas in the chamber will be one to`sixteen.

The next-lower adjustment (not illustrated) of the tube 4I should besuch as to admit air into the chamber through the sixteen additionalholes I4 and I6, so as to provide a dilution of one part in thirty-two.

The next-lower adjustment (also not illustrated) of the tube I4 shouldcarry the top Il oi' the tube 'Il below the thirty-two holes l., Il, 82and Q4. The dilution will then bein the ratio of one to sixty-four.

After each said adjustment of the tube It with respect to the tube 42,each light sniff will draw odor through the opening 10 and air throughthe holes in the mixing tube 42, into the adjustable mixing chamber 49,the diluted mixture stream thus entering into the nostrils and beingdirected toward the olfactory areas. 'I'he process should be continued(additional holes being provided in the tube 42. if needed) until, orbefore, the

`threshold of sensitivity has been reached, as

before described.

A meter is thus provided for gradually diluting the odor with a known ormeasured quantityof air in a definite ratio, to the end of determininghow many dilutions of a given odor with an odorfree atmosphere arenecessary in order to reach a determined. or a determinable, end point.

The reverse order of procedure is also possible and, in fact,recommended so that one may proceed from no sensible odor to theapproximate threshold value. This is one advantage of the instruments inFigs. 1 to 13, 19 to 27, and 31 to 33 over those of Figs. 14 to 18.

In fact, when the adjustable nose pieces 43 and 45 are employed, themeter of the present invention may be so adjusted that, in the smellingor whiiiing operation, the dilution of the gases is brought about veryaccurately, and without the necessity for employing any additionalapparatus. The said end point or indicator may be determined as asensory response,-as approximating the threshold or smallestdistinguishable dilution, as before described.

Further to the attainment of this end, it is desirable to bend the tubes39, 4|, |58 and |58 somewhat as indicated in Figs. 7, 19, 21, 31 and`32, so

' that the nose pieces 43, 4I, |58 and IBI shall be enabled toenterdirectly into the nostrils, side by side, when the observeroccupies an upright, convenient, comfortable position and, furthermore,so as to provide an adjustment to the nostril distance and otherwisesecure e.y comfortable flt of the nosepleces in the'nose. Alternatively,without such bending, the nose piece should have an eccntricallypositioned opening I I, and should be more spherically shaped, as shownat 53, Fig. 30. When the observer has to bend over into anuncomfortable, unerect, position, and when the ilt of the nosepleces ispoor, his observations are liable to be less precise.

,The nozzles should be so formed as to fit into the nose in such a waythat penetration of outside air is prevented, and yet withoutprojectingv an appreciable distance within the nostrils, as they mightotherwise touch the sensitive 1ining of the nose. For example, the topsoi' the parts IB and 3B should not be of such dimension as to permittouching more than the inner periphery of the nose. This may be'broughtabout by having the nozzles somewhat spherical. At the same time, thenozzles should be so placed as to direct the odor towards the olfactorycleft.

It may be desirable to mix the odor from the vessel 12 with a secondodor, instead of with air, in which event a container 82 may be builtabout the tube 42, as illustrated in Figs. 9 and 10, together with aninlet yI4 for admitting the second test odor to the container 82. 'I'hischamber may also serve as a reservoir of odor-free air ii the test iscarried out in a room or other environment in which the air is notodor-free, or this chamber 82 may contain an odor-absorbing substancesuch as activated carbon to pro- 4duce an odor-free air. Or the entrance84 to the chamber 82 may be capped with a vfilter of odor-absorbingsubstance of low air resistance. If desired, indeed, still a third tubeIt may be used, for mixing or blending two odor-containing gases withclear or substantially odorless air, the third tube Il being ofsubstantially the same construction as the tube 42, and the three tubes42, 4I and Il being telescopically adjustable with respect to oneanother. If it is desired to mix` with an inert or other suitable gas,instead of with air. or with a third odor, the third tube Il may becontained in a second container 8l, provided with an inlet Il, asillustrated in Fig. 10.

The principle oi' the invention may, of course, be employed with otherapparatus also. Thus, the tube 92 of Figi? 11 to 13 may have twobranches I4 and Il, the former having the single opening 1l, and .theother having a disk 88, pivotally adjustable at IMI. The disk may haveopenings |02 of diiferent size, as illustrated in Fig. 12, or aplurality oi' openings |04. Fig. 13,

all of the` same size, but grouped together to 4produce the same,geometricratio eiect,j as

. ings of different size and, if desired, of dierent shape. It is alsopossible to extend the range of the instrument by the addition of otherpluralitiesy of openings.

This may be understood from the following consideration. The same amountof gas can be caused to pass through two holes either with the aid ofthe same pressure drop through holes of the same area and shape, or'with the aid of different pressure drops through" holes ofcorrespondingly different area and shape. Assuming the gas in one ormore chambers to be at atmospheric pressure, for example, and to bedrawn into a mixing chamber by' suction of the nose, the pressure of themixing chamber lower level six openings |32;

' metal tube |24 with positions of adjustment, it is possible to obtainwill become reduced by such suction. To vary the total amount of gasdrawn into the mixing chamber under agiven pressure gradient which maybe constant or fluctuating in magnitude, either the number of holes ofthe same area and shape may be varied, or the area and the shape of theholes may be varied.

A more constant hydraulic or pressure gradient is maintained into themixing chamber and more constant resistance to the nose, with the aid'of the modicationqof Figs. 10 to 2'1 and 31 to 33. This instrumentcomprises an odor tube |06, which may or may not have an extension tube|06 attached at its lower, open end ||0, and which, like the odor tube66.15 closed at the upper end ||2, except for a small opening H0. Thisodor tube |06. also like the tube 66, is provided with a number of sideopenings, but differently arranged. There are two openings |i6,' `at thesame level, below the top H4; two lopenlevel, threeopenings |20 andeight openings |22 at ings H6 at a. lower at a lower level still; the-lowest level.

in addition to. the odor tube Hifi.y the instrument of this modiiicationcomprises an unperforated tube |24, open at both ends, and in which theodor tube |06 is telescopically slidable so as.

to cover, in successive positions of adjustments,

the openings |22, |20, H6 and ||6. The tube |24 may bereferred to as thecentral sleeve tube.

There is still a third tube |26, which may be |24 is'telescopicallyadjustable so as. to cover, successively, seven levels ofopenings. The upfpermost level contains eight openings |28; thenext-lower level seven openings |20; the nextten openings |34; the'next-lower level eight openings |36; and the last two lower levels,ytwelve openings |36 and |40, each.

The above are but lexamples of suitable numbers of holes in thesevarious'tubes.

By adjusting the odor tube |06 in the metal tube" |24, to variouspositions, and covering the the air tube |26 in various of odor and airin the desired ratios g substanmixtures of 1 to 2, 1 to 4, etc., whilemainta the next-lower level' tially the same total number of holesthrough which the air and the odor enter a mixing chamber |42, at theupper end of the air tube |26.

1n order to draw into the nose piece the undiluted odor. correspondingto 130:0, the instrument may be so set that the central sleeve tube |24shall leave all the openings ||4 to |22 in the odor tube |06 free,closing all the openings |28 to |40 in the air tube |26, as illustratedin Figs. 19 and 2l. The odor will therefore be drawn through all thesixteen holes ||4 l to |22, `and without any `air mixed therewith.

In order to obtain a dilution of 1 to 2, where pCizi, the setting of thecentral sleeve |24 would lbe such as to cover the eight holes |22 of theodor tube |06 and leave the eight holes |28 of the airv tube |26 free,as illustrated in Fig. 22. The odor and air will then be drawn into thechamber |42 in equal proportions; and again through a total of sixteenholes.

In Fig. 27, the adjustment is such that the odor is drawn through the veholes ||4 to llt and the air through the fifteen holes |28 and |30. Thedilution is now in the ratio of 1 to 4, or p0=2. 'The total number ofholes through which the air and the odor enters is twenty, not far fromsixteen.

When the parts are adjusted as illustrated in Fig. 26, the odor entersthrough the three holes ||4 to H6 and the air through the twenty-oneholes, |26, |30 and |32, a total of twenty-four holes, which is also notfar removed from sixteen.

The odor radio is 1 to 8; p0=3.

To obtain a ratio of odor to air of 1. to 16, or :iO/:4, one needs butto adjust the parts as illustrated in-Fig. 25, where only the one holeI4 admits odor to the mixing chamber |42, while the air enters throughthe fifteen holes |28 and |30, as in Fig. 27. The total oi sixteen holeshas here been restored.

Two more ratlos are possible with the instrument illustrated in Figs. 19to 27 and 31 to 33: 1 to 32 and 1 to 64:, the former giving a p0 valueof 5, and the latter of 6. AIn both cases, the odor will enter themixing chamber |42 through the single hole H4; the air, however, willenter the chamber |42 through the thirty one holes |28 to |34, andthrough the sixty-three holes |28 to |40, respectively. The total numberof holes is here 02 and 64, respectively.

in this design, therefore, the number of holes through which the odorand air mixture is drawn is substantially the same, although it doesvary from a low value of sixteen to a high value of sixty-four, theactual numbers being 16, 16, 20, 24, i6, 32 and '64, respectively. Theresistance against which the nose Works, using the instrumentmi Figs. 19to 27 and 3l to 33,`therefore is more nearly uniform, thereby disturbingless the uniform conditions and also ,the pressure gradient ordifference under which the air and the odor-containing gas are drawnthrough the holes, than is the case with` the devices illustrate'd inFigs. l to il, where there is not the same uniform resistance, nor thesame Vhydraulic or pressure gradient from the nose to the holes for thedifferent settings. Other suitable numbers of holes can be employed tokeep the total number of holes substantially constant, also for thehigher dilutions. Thus, in Figs. 31 and 32,

as in Figs. 19 to 2'1. can also be kept 1the openings |36 and |38 areeach ten in number, k

as illustrated and f each have a spring-pressed plunger and |18,

respectively, which ilt into depressions |18 provided at suitableintervals along the guide rod |18. In this modiilcation, which isentirely of m'etal, a disk III is provided for setting the instrument ontop of the ask 12.

The invention has many applications. It may,

20 for example, be used to measure the odor in a room or chamber, thetube 88 or |88 being inserted through a wall or door oi the room, andthe mixing tube l! or Ill being tree to the atmosphere, or inserted in aspecial chamber.

85 The invention has uses also in addition to odor measurement anddetermination. It is of value, for example, in diagnosis, for testingsensitivity oi' a person's'oli'actory areas against an odor of knownvalue, for a subnormal or hyper-normal,

80 odor-detecting sensitivity may readily be made is under Vatmospherictesting the apparent in accordance with the present invention. It is oi'use also in anaesthesia; by sliding the tubes relatively to each other,after an initial adjustment, it is possible, assuming that the etherpressure, to control precisely the mixture oi' ether and air so as toregulate the mixture, and obtain any desired proportion oi theseconstituents.v

In Figs. 28 and 29, there is illustrated a nonadiustable instrument thatmay, i! desired, be made wholly of glass. This instrument is notintended for the direct purpose of measuring threshold odor intensities,or din'erent odor concentrations, but for the purpose ot observing orodor conveniently and accurately by directing the odor towards theolfactory areas and without the admittance oi air that would enter thenostrils withoutits use. To .this purpose, this instrument may replacethe odorobserver tube 38 used in connection with the odor meterillustrated in Figs. 14 to 18.

It is common practice to dilute an odor-containing liquid in a bottle orjaiF I for mixing it with a dem-ed quantity or sadness water. 'nie'vessel |48 is closed by means of a stopper and the mixed contentsshaken, after which the stopper is removed, and the observer whiil's theodor. The instrument illustrated in Pigs. 38 and 29 provides a moreprecise observation or tbsting of the raw or mixed odor.

4 'Ihe bottom, open end I is inserted into the bottle I to a distancevery close to the suri'ace oi' the liquid to permit the odor to travelup the tube I into an enlarged chamber |48 to which are connected anddlltble nozzle tube |50 and a stationary nozzle tube |52. Both nostrilswill thus receive the odor-containing gas in the Jar or bottle |48 andthe measurement will be made Y under the same conditions as with theother instruments before described.

.The parts, i! -of glass, should preferably be connected by groundioihts, such as shown at .l Il. Co k stoppers may absorb odors, thoughthey y be covered with paramn to eliminate the odors. Metal Joints mayalso be used, as illusresulting trated in Figs. 3l and 32.. The stoppershown in Fig. l, too, may be made of glass, with -groundglass Joints, ora metal Joint may be employed.

Other modifications will also occur. to persons skilled in the art. Itis therefore desired that the appended claims be broadly4 construed,except where limitations may be required in view of the state of theart.'

What is claimed is:

1. An odor meter comprising a screened chamber into which odor from asolid may enter, a second chamber provided with means for admitting theodor into the chamber, andmean's for diluting the odor in substantiallygeometric ratio.

2.\An odor meter comprising a chamber provided with openings throughwhich a volume of' an odor-containing gas may be admitted into thechamber and with a plurality of equivalent openings through whichanother gas may be admitted into the chamber in volumes that are relatedto the ilrst-named volume in substantially geo'- metric ratio.

3. An odor meter comprising a chamber provided with adjustable openingsthrough which a volume of an odor-'containing gas may be adf mitted intothe chamber and with adjustable openings through which another gas maybe admitted into the chamber in volumes that are related to the ilrstvolume in substantially geometric ratio.

4. An odor meter 'comprising a chamber provided with an opening throughwhich a volume of an odor-containing gas may be admitted into thechamber and with a plurality of openings through which another gas maybe admitted into the chamber in volumes that are related to thefirst-named volume in substantially geometric ratio, a containercommunicating with the plurality oi' openings, and means for admittingsaid other gas to the container.

5. An odor meter comprising two tubes, one of the tubes having a top andbeing telescopically adjustable in the other tube to form an adjustablechamber in said other tube, said top being provided with an openingthrough which a volume of an odor-containing gas may be admitted intothe chamber, said other tube having a plurality of openings throughwhich another gas may be admitted into the chamber, the walls oi theilrst-named tube being adapted to open and close selected openings insaid other tube, depending upon the degree of telescopic adjustment ofthe tubes, and the said plurality of openings having a relation to themst-named opening such that the volumes of said other gas admitted intothe chamber through the said plurality of openings When the tubes occupypredetermined positions of relative telescopic adjustment is in sub-V.stantially geometric ratio to the volume of the closeselected-openings in said other tube. de-

pendingupon the degree oi ltelescopic adjustthe tubes having a top andbeing telescopically ment of the tubes,and means for indicating theposition of telescopic adjustment.-

'7. An odor meter comprising two tubes, one of adjustable in the othertube to form an adjustable chamber in said other tube, said top beingprovided with an opening through which a volume of an odor-containinggas may be admitted N into the chamber, said other tube having aplurality of openings through which another gas may be admitted into thechamber, the walls of the first-named tube being adapted to open andclose selected openings' in said other tube, de-

pending upon the degree of telescopic adjust-` ment of the tubes, andmeans for maintaining the tubes in `adjusted position. i

8. An odor meter comprising a tube having a plurality in its side, theodor meter comprising also a second tube telescopically adjustable inthe'iirstnamed tube in a direction toward the iirst-named openings so asto close the said-plurality of openings in successivepositions oftelescopic adjustment of the tubes, said second tube having a topprovided with an opening, the openings being all of .the same area.

9. An odor meter comprising a chamber having two branches, one of thebranches being provided with means for admitting a volumel of anodor-containing gas into the chamber, and the other branch having meansfor admitting another `gas into the chamber, the said means beingadapted to occupy a plurality of successive positions in which the gasesare admitted into the chamber in volumes that are `related to thefirst-named volume in geometric successive positions being calibrated toindicate the said substantially geometric ratio.

10. An odor meter comprising a base having two rigid tubes mounted'onthe base having nose pieces angularly disposed to each other, the nosepieces 'being' adapted to be inserted into the nostrils of a nose andhaving means for directing. an odor toward the olfactory cleft, thetubes being adjustable on the base to vary the distance between them.

il. Apparatus for measuring the odor of a gas comprising a reservoirfor'the odor-containing gas, a chamber connected with the reservoir,whereby the odor-containing gas may be drawn into the chamber from thereservoir, a reservoir tor a diluting gas connected with the chamber,whereby the diluting gas may be drawn into the chamber 'from thesecond-named reservoir, and means for maintaining the two reservoirsunder substantially the same pressures, thereby making the ratios ofdilution determinable.

l2. An odor meter comprising a chamber provided with means for admittingan odor-containing gas into the chamber, and means for diluting the gasadapted to occupy-a plurality of successive positions in which the gasis diluted in substantially geometric ratio, the said. successivepositions being calibrated to indicate the said substantially geometricratio.

13. An odor meter comprising a chamber provided with means forIadmitting a volume of an odor-containing gas into the chamber, andmeans for admitting another gas into the chamber, the last-named eansbeing adapted to occupy a plurality of successive positions in which thegases are admitted into the chamber in volumes that are related to thefirst-named volume in of openings at predetermined positions,

ratio, the said ing calibrated to indicate the said substantiallygeometric ratio.

14. An odor meter comprising a chamber, means for simultaneouslysupplying diierent gases to the chamber, a rigid tube connected with thechamber and provided with a no se piece at its free end, the nose piecebeing disposed at anangle to the tube to adapt it for entering into thenose in such position. as to direct the gases from the ,chamber directlyto the olfactory cleft.

15. Anodor meter comprising a chamber provided with means for admittingtwo odor-oontaining gases thereto, and means for controlling theadmission oi th'e gases to the chamber, the last-named means beingadapted to occupy a plurality oi'. successive positions in which thegases are admitted to the chamber in substantially geometric ratio, thesaid successive positions being calibrated to indicate the saidsubstantially geometric ratio.

16. An odor meter comprising a chamber provided with a plurality ofopenings through which an odor-containing gas and another gas may berespectively admitted into the chamber, the number of openings beingvariable in order that the gases may be admitted into the chamber in'subzles with the chamber, the tubes being bent each tube toward thenozzle.l

18. An odor meter comprising a base having two rigid tubes mountedthereon in side-by-side relation and each provided with a nose piece,the nose pieces being adapted to be inserted into the nostrils of anose, the nose pieces having means for directing an odor toward the'olfactory cleft, and the stems being adjustable on the base to vary thedistance and the angular relation between the nose pieces. 1

i9. An odor meter comprising an odor tube, a central sleeve in which theodor tube is telescopically adjustable and an air tube in which thecentral sleeve is telescopically adjustable, the air tube having achamber into which an odorcontaining gas maybe admitted from the odortube. i

20. An odor observer comprising a tube into which odor-containing gasesare adapted to enter through one end of the tube, a base at the othertoward each other from an intermediate point of end of the tube, tworigid tubes extending through the base into the iirst-named tube, theends of the said two tubes extending beyond the firstnamed tube beingprovided with nose pieces, the nose pieces being angularly adjustablewith respect to each other.

21. .An odor observer comprising a tube into which odor-containing gasesare adaptedv to enter through one end of the tube, a base at the otherend of theitube, two rigid tubes mounted on the base and communicatingwith the irstnamed tube, the free ends of the said two tubes beingprovided with nose pieces, the said two tubes being twistable on thebase'so as to direct the odor through the nose pieces towards theolfactory cleft.

22. An odor observer-comprising a tube provided with a substantiallyspherical nozzle, the nozzle having an opening communicating with thetube and that is eccentrically positioned with respect to the axis ofthe tube.

23. An odor meter comprising a chamber into vwhich odor from a solidVmay' enter, a second chamber provided with means for admitting odor fromthe mst-named chamber into the second chamber, and means for dilutingthe odor in the second-named chamber in substantially geometric ratio.

24. An odor meter comprising a chamber provided with an opening throughwhich a volume of an odor-containing gas may be admitted into thechamber vand with a plurality of openable and closable openings throughwhich another gas may be admitted into the chamber in volumes that arerelated to the first-named volume in substantially geometric ratio. 25.An odor meter comprising two tubes, one of the tubes beingtelescopically adjustable in the other tube to form an adjustablechamber between the tubes, the tubes having a' plurality of openingsthrough which two gases may be respectively admitted into the chamber, apluraiity of the openings being adapted to open and close in selectedpositions of telescopic adjustment of the tube.

26. Apparatus for measuring the odor of a gas comprising a reservoir forthe odor-containing gas, a chamber connected with the reservoir, wherebythe odor-containing gas may be drawn into the chamber from thereservoir, and means whereby a diluting gas may be drawn into thechamber from the source of supply of. the diluting gas, the reservoirand the source of supply being under substantially the same pressures,thereby making the ratios of dilution determinable.

27.. An odor meter comprising a basevhaving two rigid bent tubes mountedthereon in sideby-side relation and each provided with a lnose piece,the nose' pieces being adapted to be inserted into the nostrils of anose, the tubes being bent at such an angle that the disposition of theassembled nose piece and tubes is such as to facilitate directing anodor toward the olfactory cleft when the nose pieces are inserted intothe nostrils in a comfortable position, and the stems being adjustableon the base to vary the distance and the angular relation between thenose pieces.

28. An odor meter comprising a chamber provided with openings throughwhich different gases may be drawn by the nose into the chamber fromdifferent sources of supply of the different gases, the openings beingadjustable to vary the proportions of 'thedifferent gases drawn intothel chamber, and means for maintaining a the substantially equalpressure gradient of the different gases into the chamber.

l 29. An odor meter comprising a chamber into which gases may be drawnby the nose in varying proportions from different gas sources, means formaintaining a substantially equal pressurev gradient into the chamberfrom the gas sources,

and means for varying the areas through which the respective gases passwhile maintaining substantially equal pressure gradients, therebydetermining the ratio of. the volumes vor flows of the different gasesadmitted to the chamber.

30. An odor meter comprising two substantially concentric tubes, a thirdtube telescopically adjustable in one of the two tubes to form anadjustable chamber between the tubes, said two tubes each having aseries oi openings through which two gases may be .respectively admittedinto the chamber, the openings being adapted to open and close inselected positions of adjustment of the third tube, and the arrangementof the openings being such that. the number of openings through whichthe gases are admitted intoA the chamber is substantially constant inall positions of, telescopic adjustment of the third tube.

31. An odor observer comprising a substantially straight rigid tubehaving a nozzle at the substantially straight end of the substantiallystraight tube, the axis of the nozzle substan tially coinciding with theaxis of the tube, the nozzle being provided with an openingcommunicating with the tube and the plane of which is disposedeccentrically to the straight direction of extension of the tube.

32. An odor meter comprising a chamber provided with means for admittingtwo gases thereto, and means for controlling the admission of the gasesto the chamber in substantially geometric ratio irrespective ofvariations in the rate of ilow.

33. An odor meter comprising a chamber provided with openings throughwhich different gases may be drawn by the nose into the chamber fromdifferent sources oi supply of the dif ferent gases, the openings beingadjustable so to vary the proportions of the diflerent gases' drawn intothe chamber that they shall be drawn into the chamber in volumes thatare related to each other in substantially geometric ratio.

GORDON M. FAIR. W. F'. WELLS.

